Probing quantum resources in nitrogen-vacancy centers in diamond

We study the thermal evolution of entanglement, Bell non-locality, quantum steering, and correlated coherence in a system constituted of two nitrogen vacancy (NV) centers with dipole-dipole interaction and subjected to an external magnetic field. From the results, we observe that correlated coherence is more resilient than the other resources, so quantum tasks based on correlated coherence survive over a wider temperature range than those relying on non-local quantum correlations: correlated coherence remains nonzero up to k_BT ≈ 41.7 GHz, whereas the other three measures vanish below k_BT ≈ 0.6 GHz. We also reveal a distinct hierarchy of resilience of these quantum correlation metrics: Bell non-locality is the most fragile resource, followed by Einstein-Podolsky-Rosen (EPR)-steering and negativity. The results also indicate that the NV center parameters can be tuned for the enhancement and preservation of the quantum correlations within this system against thermal fluctuations.